Wireframe

You might say

Hold off on colors—sketch a gray page skeleton first: header, hero, three cards, footer, just the positions.

A wireframe is the page skeleton drawn in gray blocks and placeholder lines—it fixes "what goes where" before any colors or fonts.Sketch the page in gray blocks first: how tall the header is, what sits in the hero, where the button goes. With positions settled, colors and fonts come next without dragging the structure around. The division of labor: the wireframe owns the skeleton, the visual design owns the skin.
Know first
Further reading